Sensible heat flux related to variations in atmospheric turbulence kinetic energy on a sandy beach

Two field experiments were conducted in the surf zone of the Monterey Bay to explore the relationship between surf zone sea spray and sensible heat flux. Nine flux tripod towers with instrumentation designed to measure atmospheric wind speed and direction, temperature and relative humidity, as well as thermistor and pressure sensors in the surf zone, were deployed throughout the two experiments. Data analysis showed that the ocean temperature was warmer than the air temperature and the environment was mildly unstable throughout most of the two experiments. The total data set was broken into 15-minute averages and limited to onshore winds over 3m/s and a stability range of —5< ,ζ, ζ being the non-dimensional height under Monin-Obukhov Similarity Theory. Sensible heat flux was calculated using the eddy covariance method and also using the COARE 3.5 model, validated for the open ocean, and the results were compared. The model under-predicted measured results by over 50%. Sea spray sensible heat was then calculated and added to the model results; the new comparison showed that the model was nearly the same as the measured results with sea spray sensible heat added.http://archive.org/details/sensibleheatflux1094555636Lieutenant Commander, United States NavyApproved for public release; distribution is unlimited

Coastal Land Air Sea Interaction: “the” beach towers

2016 AGU Fall MeetingAs part of the Coastal Land Air Sea Interaction (CLASI) experiment, an alongshore array of 6-m high towers instrumented with ultrasonic 3D anemometers and temperature-relative humidity sensors were deployed at five sandy beaches near the high-tide line in Monterey Bay, CA, in May-June 2016. A cross-shore array of towers was also deployed from within the active surfzone to the toe of the dune at one beach. In addition, waves and ocean temperature were obtained along the 10m isobath for each beach. The dissipative surfzone was O(80m) wide. The wave energy varies among the beaches owing to sheltering and refraction by the Monterey Canyon and headlands. The tides are semi-diurnal mixed, meso-tidal with a maximum tidal range of 2m. This results in a variable beach width from the tower to the tidal line. Footprint analysis for estimating the source region for the turbulent momentum fluxes, suggests that the observations represent three scenarios described as primarily ocean, mixed beach and ocean, and primarily beach. The direct-estimate of the atmospheric stability by the sonic anemometer suggest that all of the beaches are mostly unstable except for a few occurrences in the evening during low wind conditions. The onshore neutral drag coefficient (Cd) estimated at 10m heights is 3-5 times larger than open ocean estimates. Minimal variability was found in Cd based on the footprint analysis. Beach- specific spatial variability in Cd was found related to atmospheric stability and wave energy